When the Capitol campus erupted into chaos Thursday, hundreds of Capitol Police officers sprang into action. Yet their paycheck for the work done on that traumatic day isn’t guaranteed, thanks to the government shutdown.

Gunshots reported on Capitol Hill sent Capitol Police into swift action around 2:25 p.m. Thursday, immediately implementing a lockdown of the complex and putting into motion hundreds of law enforcement officers to protect the Capitol.

Patrol officers joined Secret Service units and other law enforcement agencies in pursuit of a black car that appeared headed for the Capitol after attempting to breach White House security.

Outside, officers quickly cleared members of Congress, staffers, reporters and tourists from the East Front, sweeping them out of danger. In an effort to secure the perimeter, they popped up barricades on streets surrounding the Capitol, resulting in an unfortunate crash in which one officer sustained non-life-threatening injuries.

As some ran into the situation with their guns drawn, those stationed inside cleared the hallways of bystanders, ordering them into their offices. Guards swept lawmakers from outside balconies, locked down galleries and ordered doors locked and windows closed, keeping the Capitol community sheltered in place.

“We’re in lockdown. If you have an office, get inside,” an officer stationed near the House door yelled, sending reporters and staffers scuttling out of the way of the gun-toting responder.

Those officers, and the many others who sprang into action to contain the situation, are among the hundreds of thousands of employees being forced to work without pay during the shutdown. Because Congress has not yet cleared the budget impasse, the date of their next paycheck is not a sure thing.

The forces have been all hands on deck to field questions from tourists angry that they can’t get a tour of the Capitol and monitor the protests of disgruntled furloughed government employees who have shown up to give Congress a piece of their mind.

Senate Majority Leader Harry Reid, D-Nev., heard about the officers’ dedication Thursday. He spoke on the phone with injured officer Bryan Carter, who was hospitalized after the crash, and Reid later relayed the conversation on the floor.

When Reid asked Carter how he was doing, he said he was going to be fine, and then said: “The only thing I do every day is to make sure you and everyone who works up here is safe.”

Under shutdown protocols issued by Senate Sergeant-at-Arms Terrance Gainer, chairman of the Capitol Police Board, forces were ordered to remain “at full operational strength, fully prepared for any contingence and constantly vigilant.”

As essential employees, attendance is mandatory and all paid time off is canceled. No vacations, no sick leave, no religious holidays. Any absence from work would be considered a furlough, and refusing to come to work after being ordered to do so classifies an officer as AWOL, or absent without leave.

“As a sworn employee, you’re coming to work,” said Lt. Kimberly Schneider, a public information officer for the department.

Officers were set to receive checks on Friday for the two-week pay period that ended Sept. 30, but the next payday is not known. Whether there will be a paycheck on Oct. 20, and how much the check will total, depends on two factors: how long the shutdown lasts and what instructions Congress includes in whatever continuing resolution it passes.